1992-40524U (Prior Art 1) and 1996-316099A (Prior Art 2) disclose a high-voltage capacitor in which two through holes are formed at a distance in a single dielectric porcelain body, and separate individual electrodes and a common electrode which is common to the individual electrodes are formed on the surfaces of the porcelain body at which the through holes open.
1993-033519U (Prior Art 3) discloses a high-voltage capacitor comprising two separate dielectric porcelain body in place of a single dielectric porcelain body.
In the high-voltage capacitor device fabricated from the above-described high-voltage capacitor, the common electrode of the high-voltage capacitor is secured on the raised portion of a grounding metal by a means such as soldering. Through conductors are provided so as to pass through the through holes at the capacitor and a through hole of the grounding metal. The through conductors are soldered to the individual electrodes at the capacitor using electrode connectors or the like. An insulating case is fitted around the external circumference of the raised portion of the grounding metal so as to enclose the capacitor. An insulating cover is fitted at the other surface of the grounding metal so as to enclose the through conductors. The insulating cover is mounted so that it comes in complete contact with the internal circumferential surface of the raised portion of the grounding metal.
To oscillate the magnetron of a microwave oven, a voltage of about 4 kV0-p at a commercial frequency or at a frequency of 29 kHz to 40 kHz is applied. The magnetron thus oscillated generates undesirable radiation waves. The undesirable radiation waves have adverse effect (noise interference) on the peripheral devices. The high-voltage capacitor device is employed as a filter in the magnetron in order to eliminate the adverse effect of the undesirable radiation waves.
In the high-voltage capacitor device of Prior Art 1 or 2 employed as a filter of a magnetron, the undesirable radiation waves in the vicinities of 500 MHz, 700 MHz and 900 MHz generated in the magnetron cannot be eliminated, and have adverse effect on the peripheral devices.
In the high-voltage capacitor device of Prior Art 3 employed as a filter of a magnetron, the undesirable radiation waves in the vicinity of 900 MHz generated in the magnetron cannot be eliminated, and have adverse effect on the peripheral devices.